nForce - use for dual memory?

[gft]

I have PC2100 memory, but the barton 2500+ processor seems very attractive, partially due to it's overclock-ability and because I'm running an athlon xp 1600+, which may be too slow for half-life 2.

The problem is that my 133 MHz DDR memory doesn't work at the barton 2500+'s 166 MHz DDR bus speed. However, because the nForce chipset has dual memory controllers, it seems to me that I could run my memory at 166/2=83 MHz DDR, and because it is doubled by having two memory controllers I would effectively have pc2700 memory.

Along that same line of reasoning, if I had a CPU with a 400 MHz bus, it seems that running my memory at 100 MHz ddr, with the nForce chipset I could get effectively 400 MHz memory bus.

Please let me know if this works, and if you know of any links to benchmarks or reports of such a configuration.

Thanks!
gft

[Ramirez]

NForce2 dual channel architecture is NOT about doubling the frequency but about doubling the bandwidth,Your DDR modules will still run at their physical frequency (dual pumped 100/133/166/200>200/266/333/400Mhz) (unless if you're overclocking it off course) I'd suggest you to abandon that idea..

If you're going for a 333FSB Barton core CPU then it's really necessarily to use an appropriate memory modules which is off course DDR-333(PC2700)OR in case of Barton-400FSB CPU,DDR-400(PC3200).
The bottom line is: keep your RAM running at the same frequency as CPU (synchronously) very important with Nforce2 chipset.

[gft]

Right - it just seemed like this would work:

the bandwidth of 128 bit 100 MHz DDR = the bandwidth of 64 bit 200 MHz DDR

But I guess it doesn't. Thanks for letting me know!

gft

[Asmodian]

I just wanted to say the theoretically your right gft - with dual channel you should be able to get twice the bandwidth of single channel, or the same bandwidth at half the speed. This is not at all true in the real world due to all sorts of things all of which I do not fully understand. The thing about the NForce2 is that it's dual channel is total crap (or not even really dual channel?). I get about 5-10% bandwidth increase from using dual channel over single channel. For the nforce2 you really want fast ram too (as Ramirez said) because clock for clock the nforce2 isn't as fast as it could be, but it can run a very high clock.

I am currently running:
Abit NF7-v2.0 with bios 18 (an Nforce2 MB)
Barton 2500+ at 2.2Ghz-11x200 it will run @220FSB but not with the newest bios (a 3200+ for $85!)
OCZ Dual pack PC3500LL SDRAM (ouch, I overpaid)
Radeon 9700np

the Barton 2500 is a great chip, I got a 500Mhz overclock - runs prime95 for 24hours with no errors!

[Ramirez]

You're welcome :) actually you're very close, this is basically the idea behind Nforce2 dual channel architecture.

2x64bit DDR Modules = 1x 128bit logical Unit /Crossed Total Bandwidth.

[Solo]

Dual channel is amazing. Just to give you an example. On my Abit IC7 875P Intel board with Pentium 4 running at 3 Ghz and 1000 mhz FSB - I tried I stick of Hynix DDR400 512mb DIMM and in Sandra's memory benchmark I got about 3000. The I tried 2 x HyperX KHX 3500 in dual channel mode and got abot 5400 !!! Nice !!!

[Milkman Dan]

The way the P4 interacts with the memory bus is different than how the Athlon uses bus bandwidth.

So comparing the 875/P4 combo to the nForce2/XP combo with regards to memory bandwidth isn't a great or even applicable comparision.

Originally posted by Solo
Dual channel is amazing. Just to give you an example. On my Abit IC7 875P Intel board with Pentium 4 running at 3 Ghz and 1000 mhz FSB - I tried I stick of Hynix DDR400 512mb DIMM and in Sandra's memory benchmark I got about 3000. The I tried 2 x HyperX KHX 3500 in dual channel mode and got abot 5400 !!! Nice !!!